In certain areas of endeavor it is sometime necessary to attach long fibers such as a thread, line or glass fibers, carbon fibers, natural and synthetic fibers or animal ligament or tendon fibers to a relatively flat surface and there have developed a variety of methods for doing so. Some methods known in the art involve placing a fastener over and/or through the fiber and into the substrate. While this method does secure the fiber to the substrate, it also damages the substrate and weakens the fiber at the place it is secured to the substrate, particularly if the fastener passes through the fiber. Moreover, this method can be difficult or in effective where the substrate is either too hard to easily insert a fastener or too soft to hold the fastener, where the fiber or substrate are fragile, or where the fiber or substrate should not be damaged.
Other methods known in the art involve the use an adhesive, usually as a single glob of adhesive over the fiber to hold it to the substrate. In these methods, far more adhesive is used than is actually necessary to secure the fiber to the substrate, unnecessarily increasing the costs. Further, many of these adhesives can take a significant amount of time to dry and/or fully cure and may not hold well until that time. Also, many adhesives are not suitable for biological applications as they are toxic.
To take a somewhat broader view, some guidance may be gained from recent work done with spiders. It has been found that dragline silk (major ampullate silk) fibers that the orb weaving spiders use for locomotion and to build web frames is attached to a range of substrates such as wood, trees, and/or concrete using silk nanofibers produced by the pyriform glands on the underside of the spider's abdomen. The pyriform silk is secreted by hundreds of tiny spinnerets on the abdomen surrounding the spinneret used for spinning the dragline silk. An attachment disk of pyriform silk nanofibers is produced by movement of the anterior lateral spinnerets over the substrate, pinning the dragline silk to the substrate as it is extruded by the spinneret. (See FIGS. 1A, 1B). In fact, it has been found that these attachment discs are so strongly held on the surface that the dragline silk fibers will break before these discs will detach from the surface. It is believed that the softness and the extensibility of the hundreds of pyriform fibers attaching the dragline silk threads, combined with low peeling angles contribute to the strength of these attachment discs, which use very little material, yet produces a very strong attachment force.
What is needed in the art is a synthetic attachment disc (and related methods of forming and using them) for attaching long fibers to a wide variety of surfaces, which uses very little material, while producing a very strong attachment force.